Method and apparatus for maintaining and servicing a pressurized refrigeration system or the like

ABSTRACT

A tool for maintaining and servicing a pressurized refrigeration system or the like therein it is desirable to remove and replace a threaded check valve core without depressurizing the system. The tool includes a body member having a longitudinal passageway extending therethrough with means to provide sealing communication between one end of the passageway with the fitting in which the check valve is fitted. A removable cap sealingly engages the opposite end of the longitudinal passageway with an operating shaft extending therethrough for axial and rotary movement within the passageway. An annular sliding seal is disposed between the shaft and the removable cap. The shaft includes engaging means formed on one end thereof for releasably engaging the valve core to unthread and remove it from the fitting and withdraw it into the passageway to a position adjacent to the removable cap. A shut-off valve is mounted in the body member to alternately close and open the passageway when the valve core is withdrawn into the passageway adjacent to the cap. An additional port in the body member communicating with the passageway is also disclosed for evacuating or charging the refrigeration system through the passageway. A method for removing and replacing the valve core employing the tool is also disclosed.

United States Patent [1 1 Olson 1111 3,840,967 [451 Oct. 15, 1974 METHODAND APPARATUS FOR MAllNTAINING AND SERVICING A PRESSURIZED REFRIGERATIONSYSTEM OR THE LIKE [75] Inventor: John W. Olson, Garland, Tex.

[73] Assignee: C & D Valve Manufacturing Company, Oklahoma City, Okla.

[22] Filed: July 13, I973 {21] Appl. No.: 378,920

Related US. Application Data [63] Continuation-impart of Ser. No.343,512, March 21,

1973, abandonedv [52] US. Cl 29/213, 29/240, 137/328 [51] Int. Cl 823p19/04 [58] Field of Search 62/77, 292; 29/240, 213,

[56] References Cited UNITED STATES PATENTS 1,736,561 11/1929 Wattel29/213 2,815,038 12/1957 Laird et al. 137/328 2,899,983 8/1959 Farris251/191 3,208,133 9/1965 Morton....... 29/240 X 3,260,498 7/1966 Johnson251/191 3,299,648 1/1967 White et a1. 62/77 Primary Examinerlames L.Jones, Jr. Attorney, Agent, or Firm-Dunlap, Laney, Hessin, Dougherty &Codding [57] ABSTRACT A tool for maintaining and servicing a pressurizedrefrigeration system or the like therein it is desirable to remove andreplace a threaded check valve core without depressurizing the system.The tool includes a body member having a longitudinal passagewayextending therethrough with means to provide sealing communicationbetween one end of the passageway with the fitting in which the checkvalve is fitted. A removable cap scalingly engages the opposite end ofthe longitudinal passageway with an operating shaft extendingtherethrough for axial and rotary movement within the passageway. Anannular sliding seal is disposed between the shaft and the removablecap. The shaft includes engaging means formed on one end thereof forreleasably engaging the valve core to un thread and remove it from thefitting and withdraw it into the passageway to a position adjacent tothe removable cap. A shut-off valve is mounted in the body member toalternately close and open the passageway when the valve core iswithdrawn into the passageway adjacent to the cap. An additional port inthe body member communicating with the passageway is also disclosed forevacuating or charging the refrigeration system through the passageway,A method for removing and replacing the valve core employing the tool isalso disclosed.

5 Claims, 7 Drawing Figuresv METHOD AND APPARATUS FOR MAINTAINING ANDSERVICING A PRESSURIZED REFRIGERATION SYSTEM OR THE LIKE CROSS-REFERENCETO RELATED APPLICATION This is a continuation-in-part of applicationSer. No. 343,512, filed Mar. 21, 1973, now abandoned. I

BACKGROUND OF THE INVENTION l. Field of the Invention The presentinvention relates generally to method and apparatus for maintaining andservicing a pressurized system such as a refrigeration system or thelike, and more particularly, but not by way of limitation, to method andapparatus for removing and replacing a closure member in a pressurizedrefrigeration system without depressurizing the system.

2. Description of the Prior Art The prior art contains a number ofteachings of servicing tools which provide access to a refrigerationsystem or the like to evacuate or charge the system. One such tool isdisclosed in US. Pat. No. 3,299,648, issued to White, et al.

It should be noted, that neither the White tool nor any other knowntools permit the removal and replacement of the threaded closure memberin a pressurized refrigeration system without depressurizing the system.

It has become common practice in the refrigeration industry to provideaccess to pressurized refrigeration systems through threaded fittings inwhich a threaded check valve core is installed. Such threaded checkvalves are of the type commonly used in automobile tire valve stems andare often referred to as Schradertype valve cores. 2

It has been found that the Schrader type valve cores used inrefrigeration systems are not subject to extremely high quality controlmeasures. Approximately 50 percent of the valve cores initiallyinstalled in a refrigeration system are found to be incapable of holdingthe proper operating pressure to permit efficient operation of therefrigeration system. It is, therefore, necessary many times to replacean unsatisfactory valve core after charging a refrigeration system withrefrigerant. It is tothis industry wide problem that the method andapparatus of the present invention is directed.

SUMMARY or THE INVENTION The present invention contemplates a toolforuse in maintaining and servicing a refrigeration system or the likeequipped with an access fitting provided with a removable threadedclosure member therein. The tool includes a body member having a firstend and a second end and having a longitudinal passageway extendingtherethrough and communicating at the opposite ends thereofwith thefirst and second ends of the body member. Coupling means is carried onthe first end of the body member for removably connecting the first endof the body member to the access fitting with one end of thelongitudinal passageway in sealing communication with the accessfitting. Removable cap means is provided which is securable to thesecond end of the body member for sealing closure of the opposite end ofthe longitudinal passageway, and, alternately, for removal from the bodymember and includes an aperture formed therein substantially coaxialwith the longitudinal passageway. An operating shaft is provided whichincludes a first end and a second end and which extends through theaperture in the removable cap means, with the first end thereof disposedwithin the longitudinal passageway and with the second end thereofdisposed outside the longitudinal passageway. The removable cap meanscarries seal means for providing slidingly and rotatingly sealingengagement between the aperture in the cap means and the operating shaftso that the operating shaft may be moved axially and rotatably withinthe longitudinal passageway, The first end of the operating shaft issecured to engaging means for releasably engaging the threaded closuremember in the access fitting. Control means operatively engages thesecond end of the operating shaft for rotating and axially displacingthe engaging means within the longitudinal passageway in response tostimulus external thereto. Valve means is carried by the body memberintermediate the first and second ends thereof for alternately openingand closing the longitudinal passageway, the valve means being adaptedto close the longitudinal passageway when the operating shaft isdisplaced toward the second end of the body member. Actuating meansoperatively engages the valve means for moving the valve means betweenaposition opening and a position closing the longitudinal passageway inresponse to stimulus externaltliereto.

An object of the present invention is to provide an efficient tool formaintaining and servicing a pressurized refrigeration system or thelike.

Another object of the present invention is to provide an improved methodand tool for maintaining and servicing a pressurized refrigerationsystem which allows the removal and replacement of a defective accessvalve core in a pressurized refrigeration system without requiringdepressurization of the system.

A further object of the present invention is to provide an improvedmethod and apparatus for maintaining and servicing a pressurizedrefrigeration system which permits the removal and replacement of adefective access valve core in a refrigeration system and furtherpermits the evacuation and/or recharging of the system by means of thesame tool.

A still further object of the present invention is to provide a tool formaintaining and servicing a pressurized refrigeration system or the likewhich is economical to manufacture and simple to operate.

Other objects and advantages of the present invention will be evidentfrom the following detailed descrip-. tion when read in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FlG.'l is a schematic diagram of arefrigeration system with the tool of the present invention connected tothe high pressure side of the compressor.

FIG. 2 is a cross-sectional View of one embodiment of the presentinvention illustrating the engaging means in engagement with thethreaded check valve of the refrigeration system and with the valvemeans opening the passageway of the tool.

FIG. 3 is a cross-sectional view similar to FIG. 2 illustrating thethreaded check valve fully withdrawn from the refrigeration system intothe passageway of the tool and with the valve means closing thepassageway.

FIG. 4 is a cross-sectional view similar to FIG. 3 illustrating thethreaded check valve removed from the tool for inspection andreplacement.

FIG. 5 is an enlarged partial cross-sectional view illustrating theconstruction details of the valve core engaging chuck on the operatingshaft.

FIG. 6 is a cross-sectional view of an alternate embodiment of thepresent invention.

FIG. 7 is a cross-sectional view of another form of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingsand to FIGS. 1-5 in particular, the apparatus of the present inventionis generally designated by the reference character 10.

The apparatus 10 is a tool which includes a body member 12 having afirst end portion 14 and a second end portion 16. A cylindrical bore 18extends through the body member 12 communicating with the first andsecond end portions 14 and 16 thereof forming a longitudinal passagewaythrough the body member 12. The outer periphery 20 of the body member 12adjacent to the first end portion 14 is cylindrically shaped. Acircumferential groove 22 is formedin the outer periphery 20 andincludes first and second cylindrical surfaces 24 and 26 interconnectedby an inclined surface 28. The diameter of the second cylindricalsurface 26 is greater than the diameter of the first cylindrical surface24. v

A coupling nut 30 is rotatably secured to the first end portion 14 ofthe body member 12. The coupling nut 30 includes a cylindrically shapedinner peripheral portion 32 slidingly disposed around the outerperiphery 20 of the body member 12. The coupling nut 30 is retained onthe body member 12 by means of a snap ring 34 carried in an annulargroove 36 formed in the inner peripheral portion 32 and engaging thecircumferential groove 22 in the body member 12.

Internal threads 38 are formed in the outer end portion 40 of thecoupling nut 30. A suitable annular Neoprene gasket 42 is positionedwithin the coupling'nut 30 between the threads 38 thereof and the firstend portion 14 of the body member 12.

External threads 44 are formed on the outer periphery of the body member12 adjacent to the second end portion 16 thereof. An access cap 46 isthreadedly secured to the second end portion 16 of the body member 12 bymeans of internal threads 48 formed therein and threadedly engaging theexternal threads 44 of the body member 12. The access cap 46 includes abore 50 formed therein coaxial with the access of the bore 18 formed inthe body member 12. A first counterbore 52 is formed in the access cap46 coaxial with the bore 50. A second counterbore 54 is formed in theaccess cap 46 coaxial with the first counterbore 52 in the bore 50. Anannular retainer 56 having a cylindrically shaped outer periphery 58having a diameter slightly less than the diameter of the secondcounterbore 54 is positioned within the second counterbore 54intermediate the internal threads 48 and the first counterbore 52 formedtherein.

An operating shaft 60 having a cylindrically shaped outer peripheryextends through the bore 50 in the access cap 46 and through the annularretainer 56. The first end portion 62 of the operating shaft 60 isdisposed within the bore 18 of the body member 12. A control knob 64 isrigidly secured to the second end portion 66 of the operating shaft 60by means of a set screw 68 threadedly secured in the control knob 64 andbearing against the second end portion 66 of the operating shaft 60.

A pair of O-rings 70 are positioned within the first counterbore 52 ofthe access cap 46 and provide a fluidtight seal between the access cap46 and the operating shaft 60. The fluid-tight seal obtained by the 0-rings 70 permits the operating shaft to be axially and rotatablydisplaced relative to the access cap 46 without fluid leakage thereby.The O-rings 70 are retained in proper position within the firstcounterbore 52 by the annular retainer 56. A fluid-tight seal isobtained between the access cap 46 and the second end portion 16 of thebody member 12 by means of an O-ring 72 positioned therebetween.

The threads 44 on the body member 12 and the threads 48 on thev accesscap 46 are suitably formed such that when the cap 46 is removed from thebody member 12 suitable means for evacuating and charging (not shown) arefrigeration system maybe threadedly engaged to the threads 44 toprovide sealing engagement between said means and the body member 12 sothat a refrigeration system may be evacuated and charged withrefrigerant through the cylindrical bore 18 through the body member 12.A suitable, and industryaccepted thread for this purpose is 7/16-20thread.

As most clearly shown in FIG. 5, a suitable valve core engaging chuck 74is secured to a reduced portion 76 of the operating shaft 60 by a rollpin 78. An O-ring 80 is secured within a counterbore 82 formed in thechuck 74 near the bifurcated end thereof and is retained in properposition by the reduced portion 76 of the operating shaft 60 adjacentthereto. An axial bore 84 is formed in the first end portion 62 of theoperating shaft 60 for receiving the extending head of the valve corebeing engaged by the chuck 74. A transverse slot 86 is formed in thechuck 74 for receiving the rectangular portion of the valve core thereinfor threading and unthreading the valve core in its fitting. A bore 88is also formed in the chuck 74 coaxial with the counter-bore 82 forreceiving the head of the valve core therethrough. The inner diameter ofthe resilient O-ring is sized such that a valve core engaged by thechuck 74 will be releasably retained thereby by means of the engagementof the head of the valve core by the O-ring 80.

A shut-off valve assembly 90 is carried by the body member 12. Theshut-off valve assembly 90 includes a valve fitting 92 suitably formedon the body member 12 and extending outwardly therefrom. A lateral bore94 extends through the valve fitting 92 and partially through the bodymember 12 intersecting the cylindrical bore 18 through the body member12. The axis of the lateral bore 94 intersects the axis of thecylindrical bore 18 and is normal thereto. The diameter of the lat eralbore 94 is greater than the diameter of the cylindrical bore 18. Thelower end of the bore 94 extends completely through the cylindrical bore18 and terminates in a flat circular wall 96 formed in the body member12.

A valve stem 98 is positioned within the lateral bore 94. A control knob100 is fixedly secured to the upper end 102 of the valve stem 98 bymeans of a set screw 104.

A cylindrically shaped resilient valve member 106 is fixedly secured tothe lower end 108 of the valve stem 98. The valve member 106 ispreferably formed of a short length of resilient tubing formed of asuitable material such as Neoprene. The outer diameter of the valvemember 106 is substantially equal to the diameter of the lateral bore 94and the axial length of the valve member 106 is greater than thediameter of the cylindrical bore 18 extending through the body member12. The valve member 106 may be secured by a suitable adhesive to thecylindrical outer periphery of the lower end 108 of the valvestem 98.

i. A pair of spaced circumferential ribs 110 and 112 are formed on thevalve stem 98 with the rib 110 abutting the upper end of the resilientvalve member 106. An O-ring 114 is positioned between thecircumferential ribs 110 and 112 and provides a fluid-tight seal betweenthe valve stem 98 and the lateral bore 94. External threads 116 areformed on the valve stem 98 and extend between the control knob 100 andthe circumferential rib 112.

The valve stem 98 is secured within the valve fitting 92 by means of avalve fitting cap 118 threadedly secured to the valve fitting 92. Theexternal threads 116 of the valve stem 98 are threadedly engaged withinternal threads 120 formed in an aperture 122 in the valve fitting cap118 through which the valve stem 98 extends. i

It will be seen that by rotating the control knob 100 the valve stem 98will move axially within the lateral r bore 94 as the valve stem 98 isalternately threaded and unthreaded in the valve fitting cap 118. FIG. 2illustrates the shut-off assembly 90 in the open position with theresilient valve member 106 fully retracted within the lateral bore 94.FIG. 3 illustrates the shut-off valve assembly 90 in the closed positionwith the resilient valve member 106 closing the cylindrical bore 18through the body member 12. It will be seen that the resilient valvemember 106 extends slightly below the lower end 108 of the valve stem98. This permits the valve stem 98 to be threaded to a point wherein thelower end 108 thereof engages the flat circular wall 96 in the bodymember 12. In this position the resilient valve member 106 is axiallycompressed and forms a fluid-tight seal closing the cylindrical bore 18in the body member 12.

It should be noted at this point that the valve fitting 92 may be in theform of a separate component suitably secured to the body member 12 bymeans such as soldering or brazing, or the valve fitting 92 and the bodymember 12 may be integrally formed in one piece.

FlG. 1 schematically illustrates a conventional refrigeration system towhich the apparatus is connected. The refrigeration system includes acompressor 124 having its high-pressure side connected by means ofconduit 126 to the inlet of a condensor 128. The outlet of the condensor128 is connected by conduit 130 to an expansion valve 132. The expansionvalve 132 is connected by means of conduit 134 to'the inlet of anevaporator 136. The outlet of the evaporator 136 is connected by conduit138 to the low-pressure side of the compressor 124 thereby completingthe refrigeration loop.

An access fitting 140 is shown connected to the conduit 126 adjacent tothe high-pressure side of the compressor 124. The access fitting 140 isof the type which includes a threaded check valve core 142 installedtherein. The valve core 142 is of the typewhich is typically referred toas a Schrader-type valve core. Such valve cores are commonly used inautomotive tires and the like.

FIGS. 2-4 illustrate the tool 10 installed on the access fitting 140with the coupling nut 30 threadedly secured to the external threads 144of the access fitting 140 and with the gasket 42 providing a fluid-tightseal between the outer end of the access fitting 140 and the first endportion 14 of the body member 12 of the tool 10. The valve core 142 isshown properly secured by the valve core engaging chuck 74.

Operation of the Preferred Embodiment To operate the tool 10, the tool10 is connected to a suitable access fitting 140 by means of thecoupling nut 30 as shown in FIGS. 1 and 2. The shut-off valve assembly90 is placed in the open position as illustrated in FIG. 2 and theoperating shaft is moved to the left as viewed in FIG. 2 where the coreengaging chuck 74 is suitably engaged with the valve core 142 which isto be removed from the access fitting 140.

The valve core 142 is then unthreaded by turning the control knob 64counter-clockwise. When the valve core 142 is completelyunthreaded fromthe access fitting 140 the control knob 64 is withdrawn as far to theright as possible as illustrated in-FlG. 3. The shut-off valve assemblyis then actuated to close the cylindrical bore 18 through the bodymember 12. This is accomplished by rotating the-control knob 100 meclockwise direction until the lower end of the valve stem 108 seats onthe flat circular wall 96 in the valve body 12 thereby I providing afluid-tight seal in thetool 10.

The access cap 46 is then unthreaded from the body member 12, and theaccess cap 46, operating shaft 60 and the valve core 142 are removedfrom the body member 12.

At this point suitable means for evacuating and charging (not shown) arefrigeration system is threadedly secured to the threads 44 of the bodymember 12 to provide sealing communication between said means and theaccess fitting 140 via the cylindrical bore 18 through the body member12. The shut-off valve assembly is then actuated to open the bore 18through the body member 12. The refrigeration system carrying the accessfitting 140 may then be evacuated and charged with refrigerant throughthe tool 10. When the refrigeration system is charged, the shut-offvalve assembly is again actuated to close the bore 18 as describedabove, and the evacuating and charging means is removed from the tool10.

The valve core142 may then be inspected and replaced if necessary. Thenew valve core 142 is secured to the valve core engaging chuck 74andreinserted into the cylindrical bore 18 along with the operating shaft60. The access cap-46 is rethreaded into sealing engagement with thebody member 12.

The shut-off valve assembly is then opened fully by rotating the controlknob in a counterclockwise direction untilthe resilient valve member 106is fully withdrawn into the lateral bore 94 thereby opening thecylindrical bore 18.

The control knob 64 is then moved to the left until the check valve core142 engages the access fitting 140. The check valve core 142 is thenrethreaded into the access fitting by rotating the control knob 64 in aclockwise direction until the check valve core seali unthreading thecoupling nut 30.

Description of the Embodiment of FIG. 6

FIG. 6 illustrates a slightly modified tool 10a which includes anevacuating and charging fitting 146 formed on and extending outwardlyfrom a slightly modified body member 12a. The fitting 146 includes alaterally extending port 148 extending therethrough and communicatingbetween the outer end thereof and the cylindrical bore 18 through thebody member 12a. A conventional threaded check valve core of theSchradertype 150 is threadedly secured within the fitting 146. Thefitting 146 further includes external threads 152 formed thereon toprovide means for engagement with suitable means for evacuating andcharging (not shown) a refrigeration system through the tool 10a.

Operation of the Embodiment of FIG. 6

In operation the tool 10a is first secured to the access fitting 140 asdescribed above. Similarly, the check valve core 142 is removed from theaccess fitting 140 and withdrawn fully to the right within the bore 18as viewed in FIG. 6. With the shut-off valve assembly 90 in the openposition, the refrigeration system may now be evacuated and chargedthrough the evacuation and charging fitting 146.

It will be readily apparent that the tool 10a may also be used to removeand replace a defective check valve core 142 as described in detailabove for the tool 10. This should preferably be done prior toevacuating and charging the refrigeration system.

Description of the Embodiment of FIG. 7

' bore 94 of the shut-off valve assembly 90. It will be seen that theport 148 of the evacuation and charging fitting 146 communicates withthe interior of the body member 12b through the flat circular wall 96formed therein.

The configuration of the tool 10b permits a slightly shorter body member12b, and simplifies machining required in the construction of the tool10b.

Operation of the tool 10b isidentical to that described for the tool 10aand therefore will not be described in detail again.

It will be seen from the foregoing detailed description of the presentinvention that the various embodiments thereof and the methods for theirutilization described therein readily obtain the objectives set forth.Changes may be made in the construction and arrangement of parts orelements of the various embodiments described herein without departingfrom the spirit and scope of the present invention as defined herein.

What is claimed is:

1. A tool for use in maintaining and servicing a conventionalrefrigeration system equipped with a threaded access fitting providedwith a removable threaded closure member therein, comprising:

a body member having a first end, a second end and having a longitudinalpassageway extending therethrough and communicating at the opposite endsthereof with the first and second ends of said body member;

coupling means carried on the first end of said body member forremovably connecting the first end of said body member to said accessfitting with one end of said longitudinal passageway in sealingcommunication with the access fitting;

removable cap means securable to the second end of said body member forsealing closure of the opposite end of said longitudinal passageway,and, alternately, for removal from said body member, and including anaperture formed therein substantially coaxial with the longitudinalpassageway;

an operating shaft having a first end and a second end and extendingthrough said aperture in said removable cap means, with the first endthereof disposed within said longitudinal passageway and with the secondend thereof disposed outside said longitudinal passageway;

means carried by said removable cap means for providing slidingly androtatingly sealing engagement between said aperture in said cap meansand said operating shaft so that said operating shaft may be movedaxially and rotatably within said longitudinal passageway;

engaging means secured to the first end of said operating shaft forreleasably engaging and retaining said threaded closure member in saidacesss fitting;

control means operatively engaging the second end of said operatingshaft for rotating and axially displacing said engaging means withinsaidlongitudinal passageway in response to stimulus external thereto;

valve means carried by said body member intermediate the first andsecond ends thereof for-alternately openingand closing said longitudinalpassageway, said valve means being adapted to close said longitudinalpassageway when said operating shaft is displaced toward the second endof said body member, said valve means including;

a valve fitting formed on said body member and extending laterallytherefrom;

a lateral cylindrical bore extending through said valve fitting and aportion of said body member and communicating between said longitudinalpassageway and the outer end of said valve fitting;

a valve stem having a first end portion and a second end portion, withthe first end portion thereof disposed within said lateral bore and withthe second end portion extending beyond the outer end of said valvefitting;

actuating means operatively engaging the second end portion of saidvalve stem for moving said valve means between a first position openingand a second position closing said longitudinal passageway in responseto external force applied thereto;

external threads formed on said valve stem intermediate the first andsecond end portions;

valve cap means threadedly engaged with said external threads of saidvalve stem for securing said valve stem to said valve fitting so thatrotation of said .valve stem relative to said valve cap means and saidvalve fitting by said actuating means causes corresponding axialmovement of said valve stem within said lateral bore;

resilient valve member means fixedly secured to a laterally extendingport formed in said body memand encircling the first end portion of saidvalve ber intermediate said valve means and the second stem andextending a distance beyond the first end of said body member andcommunicating beend portion of said valve stem, said valve memtween saidlongitudinal passageway and the exteber means being slidably disposedwithin said latrior of said body member. I eral bore for moving betweena first position 3. The tool as defined in claim 2 characterizedfurwithin said lateral bore and opening said longituther to include:dinal passageway, and a second position within a Schrader-type valvecore removably threadedly seand closing said longitudinal passageway;cured within said laterally extending port.

a pair of longitudinally spaced circumferential ribs 4. The tool asdefined in claim 1 characterized furformed on said valve stem with oneof said ribs ther to include:

abutting said resilient valve member means, said a laterally extendingport formed in said body memribs each having a diameter slightly lessthan the ber intermediate the first and second ends thereof diameter ofsaid lateral bore and slidingly disdisposed opposite said valve fittingand aligned coposed therein in all positions of said valve stem axialwith said lateral bore extending through said relative to said valvefitting; and valve fitting and communicating between said lonannularresilient seal member means disposed begitudinal passageway and theexterior of said body tween said circumferential ribs for providing amember. sliding fluid-tight seal between said valve stem 5. The tool asdefined in claim 4 characterized furand said lateral bore in allpositions of said valve ther to include: stem relative to said valvefitting. a Schrader-type valve core removably threadedly se- 2. The tooldefined in claim 1 characterized further cured within said laterallyextending port. to include:

1. A tool for use in maintaining and servicing a conventionalrefrigeration system equipped with a threaded access fitting providedwith a removable threaded closure member therein, comprising: a bodymember having a first end, a second end and having a longitudinalpassageway extending therethrough and communicating at the opposite endsthereof with the first and second ends of said body member; couplingmeans carried on the first end of said body member for removablyconnecting the first end of said body member to said access fitting withone end of said longitudinal passageway in sealing communication withthe access fitting; removable cap means securable to the second end ofsaid body member for sealing closure of the opposite end of saidlongitudinal passageway, and, alternately, for removal from said bodymember, and including an aperture formed therein substantially coaxialwith the longitudinal passageway; an operating shaft having a first endand a second end and extending through said aperture in said removablecap means, with the first end thereof disposed within said longitudinalpassageway and with the second end thereof disposed outside saidlongitudinal passageway; means carried by said removable cap means forproviding slidingly and rotatingly sealing engagement between saidaperture in said cap means and said operating shaft so that saidoperating shaft may be moved axially and rotatably within saidlongitudinal passageway; engaging means secured to the first end of saidoperating shaft for releasably engaging and retaining said threadedclosure member in said acesss fitting; control means operativelyengaging the second end of said operating shaft for rotating and axiallydisplacing said engaging means within said longitudinal passageway inresponse to stimulus external thereto; valve means carried by said bodymember intermediate the first and second ends thereof for alternatelyopening and closing said longitudinal passageway, said valve means beingadapted to close said longitudinal passageway when said operating shaftis displaced toward the second end of said body member, said valve meansincluding; a valve fitting formed on said body member and extendinglaterally therefrom; a lateral cylindrical bore extending through saidvalve fitting and a portion of said body member and communicatingbetween said longitudinal passageway and the outer end of said valvefitting; a valve stem having a first end portion and a second endportion, with the first end portion thereof disposed within said lateralbore and with the second end portion extending beyond the outer end ofsaid valve fitting; actuating means operatively engaging the second endportion of said valve stem for moving said valve means between a firstposition opening and a second position closing said longitudinalpassageway in response to external force applied thereto; externalthreads formed on said valve stem intermediate the first and second endportions; valve cap means threadedly engaged with said external threadsof said valve stem for securing said valve stem to said valve fitting sothat rotation of said valve stem relative to said valve cap means andsaid valve fitting by said actuating means causes corresponding axialmovement of said valve stem within said lateral bore; resilient valvemember means fixedly secured to and encircling the first end portion ofsaid valve stem and extending a distance beyond the first end portion ofsaid valve stem, said valve member means being slidably disposed withinsaid lateral bore for moving between a first position within saidlateral bore and opening said longitudinal passageway, and a secondposition within and closing said longitudinal passageway; a pair oflongitudinally spaced circumferential ribs formed on said valve stemwith one of said ribs abutting said resilient valve member means, saidribs each having a diameter slightly less than the diameter of saidlateral bore and slidingly disposed therein in all positions of saidvalve stem relative to said valve fitting; and annular resilient sealmember means disposed between said circumferential ribs for providing asliding fluid-tight seal between said valve stem and said lateral borein all positions of said valve stem relative to said valve fitting. 2.The tool defined in claim 1 characterized further to include: alaterally extending port formed in said body member intermediate saidvalve means and the second end of said body member and communicatingbetween said longitudinal passageway and the exterior of said bodymember.
 3. The tool as defined in claim 2 characterized further toinclude: a Schrader-type valve core removably threadedly secured withinsaid laterally extending port.
 4. The tool as defined in claim 1characterized further to include: a laterally extending port formed insaid body member intermediate the first and second ends thereof disposedopposite said valve fitting and aligned coaxial with said lateral boreextending through said valve fitting and communicating between saidlongitudinal passageway and the exterior of said body member.
 5. Thetool as defined in claim 4 characterized further to include: aSchrader-type valve core removably threadedly secured within saidlaterally extending port.